DC7: Synergistic promotion of methane and nutrient recovery by engineered biochar-based materials

Project title: Synergistic promotion of methane and nutrient recovery by engineered biochar-based materials (WP2)

Host Institution: University of Aveiro

Country: Portugal

Supervisor: Isabel Capela (PhD promoter); Co-supervisors: Dominique Patureau (INRAE)

Objectives: To perform side-by-side comparisons of various functionalized biochars to assess their effectiveness in the anaerobic digestion of sludges for biogas enhancement and/or efficient capture of agronomically relevant nutrients N and P from the digestate.

DC7 will develop functionalised biochars (with/without embedded nanomaterials) to improve sludge resource recovery in the form of fuels (biogas) and nutrients (N, P). DC7 will engineer biochar-based materials (EBM) to enhance the methane yield during anaerobic digestion and facilitate the recovery of fertiliser nutrients. DC7 will identify appropriate processing conditions leading to (i) the activation (doping) of biochar, (ii) the synthesis of catalyst nanoparticles to be used (metal(oxides)), and (iii) the efficient coupling of the catalyst to the biochar support (e.g., cation adsorption, wet impregnation or chemical precipitation), which will enable obtaining biochar-based catalysts with enhanced catalytic activity to reach the objectives set forth. DC7 will study the catalytic influence of EBMs on methane production during long-term experiments in continuous lab-scale bioreactors (Type Eppendorf BioFlo® 320). DC7 will investigate the influence of EBMs on nutrients capture and recovery. DC7 will also correlate the key physico-chemical properties of the EBMs (i.e., crystalline structure, specific surface area and porosity, surface charge, pH, and surface functional groups) with the anaerobic digestion performance in terms of process stability, waste stabilisation, energy production and nutrient recovery. DC7 will identify the key pollutants in the selected sludges and follow up on their microbial degradation and/or adsorption onto the EBM. DC7 will monitor the microbial community dynamics to gain insights in the augmented biological activity during digestion with EBM-addition.

Expected Results: Optimized anaerobic digestion strategy with inclusion of EBM to simultaneously increase methane production and recover/capture nutrients (N and P) from the digestate for future agriculture application.

Enrolment in Doctoral degree(s): Doctoral Program in Environmental Sciences and Engineering, University of Aveiro (PT)

Planned secondments:

• INRAE (Sup.: D. Patureau): M20-23 (4 months): Assessing the agronomic value of (treated) sludge and digestate, and their potential as fertilising agents for future application in agriculture.
• CTIC (Sup.: J.M.A. Salguiero Gaiao & A. Marques): M29-31 (3 months): On-site validation of EBM technology and economic assessment; training in industrial management methodologies of sludge streams.